All the documents say that a Wanderer dinghy should be supported under the keel; not under the sides and bilge keel. Mine wasn’t supported under the keel, plus the trolley had bent (probably due to the forces putting the boat on and off the trailer before I built the ramps).
Commercial boat trailer blocks were the wrong size, so I decided to use some iroko offcuts. Iroko is a hardwood that is very tough and weather resistant – ideal for this application. It is probably a bit harder than a rubber block but I don’t think that is significant in this application – the load is taken on the keel protection strips.
The hardest bit was cutting out the existing plastic tube while the boat was on the trolley. I’m happy with the result – the boat will now rock very slightly from side to side as recommended on the Wayfarer and Wanderer websites. I’ve also inserted more iroko supports between the trolley and keel so the boat is now correctly supported.